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Abstract:

An overlay list of MSAG-valid addresses is created for use in lieu of (or
in addition to) the lat/lon or postal address which otherwise would go
with an E911 VoIP 911 call. This overlays the nation with a series of
MSAG-addressed polygons, with center points identified in those polygons,
and MSAG-valid addresses provided to the PSAPs for those centers,
preferably along with the original latitude/longitude coordinates.

Claims:

1-18. (canceled)

19. A method of providing location information to a public safety
answering point (PSAP), comprising: receiving, at a physical server,
latitude/longitude information associated with a
voice-over-Internet-protocol (VoIP) caller device; retrieving, at said
physical server, an MSAG-valid address associated with a Master Street
Access Guide (MSAG)-addressed polygon mapped to said latitude/longitude
information; and providing said MSAG-valid address to a public safety
answering point (PSAP).

20. The A method of providing location information to a public safety
answering point (PSAP) according to claim 19, further comprising:
providing said latitude/longitude information to said PSAP.

21. The A method of providing location information to a public safety
answering point (PSAP) according to claim 19, wherein: said PSAP is
responsible for a center point of said MSAG-addressed polygon.

22. The A method of providing location information to a public safety
answering point (PSAP) according to claim 19, wherein: a center point of
said MSAG-addressed polygon is associated with said MSAG-valid address.

23. The A method of providing location information to a public safety
answering point (PSAP) according to claim 19, wherein: at least some, but
not all, of a plurality of MSAG-valid addresses are defined by a street
address of a corresponding cell tower.

24. The method providing location information to a public safety
answering point (PSAP) according to claim 19, wherein: each of a
plurality of MSAG-addressed polygons are defined by a single street
address.

25. The method of providing location information to a public safety
answering point (PSAP) according to claim 24, wherein: said single street
address is a street address of an approximate center of each of a
respective plurality of MSAG-addressed polygons.

26. The method of providing location information to a public safety
answering point (PSAP) according to claim 19, wherein: each of a
plurality of existing MSAG-addressed polygons is defined by a single
street address.

27. The method of providing location information to a public safety
answering point (PSAP) according to claim 19, wherein: each of a
plurality of MSAG-addressed polygons are defined by a plurality of
latitude/longitude coordinates.

[0003] This invention relates generally to wireless devices and voice over
Internet Protocol (VoIP) technologies. More particularly, it relates to
the provision of 911 services for VoIP users to a Public Safety Answering
Point (PSAP).

[0004] 2. Background of the Related Art

[0005] The E911 industry is challenged with being able to automatically
deliver location information to the Public Safety Answering Points
(PSAPs) for Voice Over Internet Protocol (VoIP) devices.

[0006] FIG. 3 shows a conventional E911 VoIP scenario.

[0007] In particular, as shown in FIG. 3, a VoIP carrier 100 includes a
call server 202 and an Emergency Services Gateway (ESGW) 204.

[0008] A service bureau 120 includes a network location information server
(LIS) 206, a Session Initiated Protocol (SIP) server (redirect) 208, and
a VoIP positioning center (VPC) 210. Also included in the service bureau
120 is an Emergency Services Zone (ESZ) route database (DB) 220, and a
validation database (DB) 230.

[0009] Also within the network are the Public Switched Telephone Network
(PSTN) 130, a selective router 140, a Public Safety Answering Point
(PSAP) 180, an Automatic Location Identification (ALI) database 190, a
Master Street Address Guide (MSAG) 195, an Internet Protocol (IP) phone
150, a provisioning system 160, and a local Location Information Server
(LIS) 170.

[0020] In step 10, the Service Bureau 120 matches the ESQK and returns
location information.

[0021] Provision of an acceptable location for a VoIP device (particularly
for a mobile VoIP device) presents a number of challenges, not the least
of which is Metro Street Address Guide (MSAG) validation of a location
for a VoIP E911 caller.

[0022] In particular, current Public Safety infrastructure is heavily
wedded to wireline interfaces and to the notion of every E911 caller
having a street address-not simply to the notion that latitude/longitude
coordinates is more amenable to todays mobile phone culture. The entire
conventional call scenario depicted in FIG. 4 presumes that a database
record exists that identifies the location of the customer and that
exists as an MSAG-validated address. In reality, this is not necessarily
the case. Nevertheless, current PSAP architectures have entire response
procedures built around street addresses only, and use the street address
as a key to a table for looking up the appropriate emergency response.
Accordingly, the bottom line is that conventional PSAPs require that
location information be MSAG validated to guarantee that the PSAP
database lookup will not fail.

[0023] Fundamentally, MSAG is a legacy requirement from PSAPs that did
(and some still do) have "dumb" terminals that receive the call and
display the address information to the call taker. In early PSAP systems,
information delivery was slow and cumbersome, so the industry worked on
developing a set of abbreviations that would allow an address to fit into
about 20 characters.

[0024] Wireless Phase I requirements defined by NENA provide E9-1-1 for
VoIP using PSAP administrative lines. Wireless Phase II requirements
defined by NENA provide E9-1-1 for VoIP across traditional 9-1-1
channels. In wireless Phase II, the location of the caller is dynamically
extracted from the network. This results in a latitude/longitude
(lat/lon) coordinate being provided to the PSAP. Those PSAPs which have
been upgraded to handle lat/lon receive the information and display it on
a screen driven by a Graphical Information System (GIS), i.e., they see a
map with a "caller is here" flag or dot. Such a conventional system is
suitable in PSAPs which have upgraded to handle these Wireless Phase II
calls (currently somewhere north of 40% of all PSAPs). However, older
PSAPs still need address information, and they expect to receive an
MSAG-validated address. So, for wireless, the address is given as the
center of the cell site/sector which is serving the caller. Not very
precise, but good enough to get emergency services in a vicinity of a
wireless caller.

[0025] With Voice Over Internet Protocol (VoIP) usage, it is desirable to
apply a similar model as is done in wireless. In other words, it is
desirable that location information be dynamically extracted from the
network, and presented to the PSAP. Unfortunately, VoIP systems, being
based on the ubiquitous Internet, do not always have the luxury of a cell
site/sector overlay to fall back on. In other words, a VoIP caller can
make a 911 call from anywhere in the country, but there is no credible
database of MSAG-validated addresses for the Internet routers to deliver
the 911 call.

[0026] There is a need for a way for VoIP users to have the best of both
worlds-provision of location information in latitude/longitude (lat/lon)
coordinates to a PSAP, while at the same time providing the PSAP with an
MSAG validated location.

SUMMARY OF THE INVENTION

[0027] In accordance with the principles of the present invention, an
overlay list of MSAG-valid addresses is created for use in lieu of (or in
addition to) the lat/lon or postal address which otherwise would go with
an E911 VoIP call. The invention overlays the nation with a series of
MSAG-addressed polygons, with center points in those polygons identified
and MSAG-valid addresses provided for those center points.

[0028] A metro street address guide (MSAG) validation database in
accordance with another aspect of the present invention comprises a
plurality of validated street addresses. Each of the plurality of
validated street addresses is correlated with a polygon area defined by
latitude/longitude coordinates.

[0029] A method of generating entries in an MSAG validation database in
accordance with yet another aspect of the present invention comprises
defining, in an MSAG validation database, a plurality of newly defined
MSAG-addressed polygons having a greater density than a plurality of
existing MSAG-addressed polygons. The plurality of existing
MSAG-addressed polygons are replaced in the MSAG validation database with
the plurality of newly defined MSAG-addressed polygons.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 depicts an exemplary state or region defined by a plurality
of MSAG-addressed polygons, in accordance with the principles of the
present invention.

[0031] FIG. 1A shows a further increase in the density of MSAG-addressed
polygons with respect to a single MSAG-addressed polygon shown in FIG. 1.

[0032] FIG. 1B shows yet another increase in the density of MSAG-addressed
polygons with respect to a single MSAG-addressed polygon shown in FIGS. 1
and 1A, to emphasize the point that the street addresses of any given
polygon will continually become more and more accurate over time, as
manpower and technology allows a greater density of MSAG-addressed
polygons to be defined.

[0033] FIG. 2 shows a few exemplary entries in an MSAG-addressed polygon
validation database, in accordance with the principles of the present
invention.

[0036] As VoIP wireless devices increase in numbers and usage, it is
desired that VoIP calls be allowed into the PSAP E911 network using an
otherwise conventional wireless interface. As technology progresses,
greater numbers of communication devices are mobile. Mobile devices by
definition do not have a static street address indicating their current
mobile position, but rather have a lat/lon coordinate. The inventor
herein recognizes that with respect to E911 requirements for locating all
callers, even VoIP callers (particularly wireless VoIP callers) should be
tracked by lat/lon coordinates rather than by street addresses.

[0037] The invention allows passage of a Lat/Lon coordinate to a PSAP,
rather than a street address, as a current location of a VoIP user. In
this way, problems associated with MSAG validation of VoIP users are
avoided, and the public safety world is moved forward into the reality
and growing popularity of VoIP technology.

[0038] FIG. 1 depicts an exemplary state or region defined by a plurality
of MSAG-addressed polygons, in accordance with the principles of the
present invention.

[0039] In particular, as shown in FIG. 1, an exemplary state 250 initially
has a plurality of MSAG-addressed polygons 201-216 covering 100% of the
area covered by the state (including waterways which wouldn't have a
street address). As shown in the magnified view of a selected
MSAG-addressed polygon 210, each MSAG-addressed polygon 201-216 has a
center point (or approximate center point) 200 defined therein.

[0040] In accordance with the principles of the present invention, an
overlay list of MSAG-valid addresses is created for use in lieu of (or in
addition to) the lat/lon which otherwise is determined for a VoIP 911
call. The overlay list is comprised of a series of polygons that together
overlay the nation, preferably with total coverage, and preferably
without any overlap. Each polygon has a center point identified, and an
MSAG-valid address determined. Whenever an E911 VoIP caller dials 9-1-1,
their lat/lon is determined, and then the network maps the lat/lon into
an appropriate one of the MSAG-addressed polygons. The MSAG-valid address
for the matched polygon is provided to the responsible PSAP for that
center point, preferably along with the original latitude/longitude
coordinates.

[0041] When an E911 call is placed, a voice positioning center (VPC) in
accordance with the principles of the present invention receives the
lat/lon coordinate location information of a VoIP caller, maps it into
one of the defined MSAG-addressed polygons, and then delivers the center
point MSAG-valid address of the matched MSAG-addressed polygon as the
MSAG-validated address of the caller. In a preferred embodiment, the
latitude/longitude coordinate is also provided to the PSAP along with the
MSAG-valid address for their use in mapping should they have such
capability.

[0042] In this way, a similar level of coverage is provided as one gets
with wireless today. Initially, the defined polygons may be defined over
large areas, e.g., over existing wireless cell towers, with shapes
generally conforming to the cell tower's coverage.

[0043] FIG. 1A shows a further increase in the density of MSAG-addressed
polygons with respect to a single MSAG-addressed polygon shown in FIG. 1.

[0044] In particular, as shown in FIG. 1A, over time, the size of the
polygons can be decreased (increasing the density) as a larger number of
MSAG-validated addresses become available to work from. For instance,
with respect to the selected MSAG-addressed polygon 210, over time it has
been redefined into four new, smaller MSAG-addressed polygons 210a-210d,
each having their own center points (or approximate center points)
defined, and a street addressed associated therewith.

[0045] Thus, as the MSAG-addressed polygon database grows, the polygons
shrink in coverage size. Eventually it is anticipated that an MSAG-valid
postal address would become available for every possible position in the
country, albeit some with larger accuracy (i.e., a larger MSAG-addressed
polygon) than others.

[0046] FIG. 1B shows yet another increase in the density of MSAG-addressed
polygons with respect to a single MSAG-addressed polygon shown in FIGS. 1
and 1A, to emphasize the point that the street addresses of any given
polygon will continually become more and more accurate over time, as
manpower and technology allows a greater density of MSAG-addressed
polygons to be defined.

[0047] In particular, as shown in FIG. 1B, a single MSAG-addressed polygon
210a shown in FIG. 1A has later been replaced with definitions of three
MSAG-addressed polygons 210e-210g, again each with an associated street
address at an approximate center point respectively.

[0048] FIG. 2 shows a few exemplary entries in an MSAG-addressed polygon
validation database 530, in accordance with the principles of the present
invention.

[0049] In particular, as shown in FIG. 2, an MSAG-addressed polygon
database 260 is built from MSAG-validated addresses that have precise
locations and around which lat/lon polygons are created.

[0050] In entry 261, MSAG-addressed polygon 201 shown in FIG. 1 is defined
by given lat/lon boundary vectors, and a center point having a street
address of "10165 Main St., Farmington, Md.". It is this street address
that is provided to the appropriate PSAP for any E911 VoIP caller having
a current location at a time of placing the E911 call within the polygon
defined by the defined lat/lon boundary vectors.

[0052] Note that the lat/lon boundary vectors may be defined in any
appropriate manner, preferably by a list of lat/lon coordinates defining
points along the boundary for the given MSAG-addressed polygon. Other
possible definitional techniques might include other geometric shapes
such as a square, circle, etc. A polygon having a virtually infinite
number of coordinate points defining the boundary thereof is preferable.

[0053] Importantly, overlapping areas in the defined areas for
MSAG-addressed polygons are eliminated by designation of the overlap area
to one of the overlapping MSAG-addressed polygon to avoid duplicity in
coverage areas by more than one MSAG-addressed polygon. While this
doesn't present a problem in areas covered by a common PSAP, ambiguity
would result from overlapping MSAG-addressed polygons in boundary areas
of coverage between two (or more) PSAPs.

[0054] Thus, any VoIP lat/lon coordinate that falls into a given
MSAG-addressed circle becomes associated with the particular street
address of the center of that MSAG-addressed polygon.

[0055] The `center` of a MSAG-addressed polygon may be determined in any
appropriate manner. For instance, the center of a polygon may be
determined mathematically, and a street address searched for that
particular point. If no street address is known or existent for that
particular center point, then a closest street address to that center
point is preferably assigned to that MSAG-addressed polygon. Thus, the
best of both worlds for a VoIP user is achieved, with the ability to pass
a lat/lon coordinate AND an MSAG-valid street address to a PSAP.

[0056] Mapping of a lat/lon coordinate into the proper MSAG-addressed
polygon, and the determination of the MSAG street address for that
MSAG-addressed polygon, is preferably performed before a PSAP receives
the call (e.g., by the wireless service provider). However, the PSAP may
receive only the lat/lon, and perform, or request performance of, the
MSAG-addressed polygon mapping, within the principles of the present
invention.

[0057] Over time, the set of mappings (i.e., MSAG-addressed polygons) will
become more comprehensive, allowing use as they continually improve. In
particular, MSAG-addressed polygons may initially be defined simply
around coverage areas of existing wireless cell towers that have a known
precise lat/lon coordinate and street address. Over time more precise
lat/lon coordinate associations for known MSAG-valid addresses can be
collected to form a more comprehensive MSAG-addressed polygon mapping
capability. As the MSAG-validated polygons become smaller and more dense,
the accuracy returned to the PSAP will get better and better, allowing
them to use their current wireline methods for dispatching assistance.
Thus, accuracy of the street addresses of MSAG-addressed polygons will
get better and better over time--allowing better and better association
to a more accurate valid MSAG address, allowing Public Safety to respond
appropriately to wireless E911 calls--even from wireless VoIP callers.

[0058] Though important for VoIP wireless callers, the invention has
application to wireless devices in general. For instance, today's
wireless world does a simple database lookup to provide the
MSAG-validated street address of the wireless E911 caller as it
corresponds to the address of the cell site/sector ID of the tower being
used. The street address of the wireless tower used by the wireless E911
caller is identified, the street address of that tower is looked up in a
table, and then an MSAG-validated street address of the tower is
returned. If a PSAP only supports Phase I wireless, only the street
address of a wireless E911 caller is sent as the street address of the
cell-site and sector of the cell tower carrying the call. However, the
present inventor realizes that a very precise (albeit unused) lat/lon
positional coordinate location may be available for that wireless E911
caller. With the present invention, a more precise location can be mapped
to a better MSAG-validated street address, with a better location
ultimately being passed to the PSAP than merely the street address of the
cell tower as in current Phase I E911 networks.

[0059] When a call is received, location information of the caller may be
extracted in real time. In conventional systems this is an entered street
address, but for mobile VoIP, precise location information is
automatically extracted from the network. When the precise lat/lon
coordinate location of the caller is obtained using any suitable method
(e.g., street address input, GPS lat/lon, GPS-TV lat/lon, etc.), a GIS
engine correlates the perceived location of the caller with one of the
MSAG-addressed polygons.

[0060] Alternatively, the MSAG database and PSAP mapping system in
accordance with the principles of the present invention may be used to
construct a geographical mapping of location-oriented polygons, and
association of the same with corresponding MSAG-validated addresses.

[0061] In particular, the extracted x,y (lat/lon) positional coordinate
may be placed on a regional or other graphical map. The MSAG-addressed
polygon that this lat/lon positional coordinate falls into is identified,
and the appropriate MSAG-validated address derived and sent to the
appropriate public safety answering point.

[0062] The MSAG-validated address may be passed along with the lat/lon
coordinate. However, if appropriate, just the street address may be
passed to the PSAP if that is all the particular PSAP desires or
requires.

[0063] Thus, especially useful is application to the wireless situation
where the PSAP is only Phase I (i.e., the relevant PSAP can only accept
an MSAG-validated address, which it expects to be the address of the
relevant cell site/sector.) In accordance with the principles of the
present invention, instead of just the conventional cell site/sector
address currently provided to Phase I PSAPs, a street address more
closely relevant to the precise lat/lon current location coordinates of
the caller can be passed to the Phase I PSAP. This is a significant
improvement over Phase I E911 location reporting as it exists today.

[0064] The invention preferably also passes any kind of error information
to the PSAP as well. (Phase II allows passage of a confidence factor and
a correlation factor, representing some level of accuracy).

[0065] Thus, public safety is advanced a great deal by implementation of
an approach that allows them to use their current response methods tied
to street addresses, yet E911 wireless callers and their providers need
only know the lat/lon coordinate of their current location.

[0066] While the invention has been described with reference to the
exemplary embodiments thereof, those skilled in the art will be able to
make various modifications to the described embodiments of the invention
without departing from the true spirit and scope of the invention.